Starting this month, Google is making changes to the way it captures and reports on conversions in AdWords in the response to Apple’s coming Safari update. In June, Apple introduced Intelligent Tracking Prevention, an initiative aimed at limit third-party trackers from capturing cross-site browsing data, in the next version of Safari, coming out this fall. The move has implications for ad performance tracking for Google and others. On Thursday, Google sent an email to AdWords advertisers outlining changes it is making in response to Intelligent Tracking Prevention. In short, with ITP, third-party cookies that are determined to be able to track users across sites can only be used for 24 hours from the time a user visits a website via Safari. After 24-hours, the third-party cookies can only be used for log-in purposes. The cookies are purged entirely after 30 days. This means that unless a user converts within 24-hours of last visiting an advertiser’s site after clicking an AdWords ad, for example, the conversion attribution will be lost. With Safari accounting for nearly 50 percent of mobile web traffic share in North America, ITP has the potential to wreak havoc on mobile ad conversion attribution. ITP is aimed largely at limiting pervasive retargeting practices rather than disrupting advertisers’ ability to track ad campaign performance. Google is addressing ITP with a method in keeping with Apple’s guidance around ad attribution, which states, “We recommend server-side storage for attribution of ad impressions on your website. Link decoration [ i.e. padding links with information]…